(a) If the earth did not have atmosphere, would its average surface temperature be higher or lower than what it is now ? Explain.(b) An EM wave exerts pressure on the surface on which it is incident. Justify.

(a) Average surface temperature will be lower. Because there will be no green house effect in absence of atmosphere.(b)Since electromagnetic waves carry both energy and momentum, therefore, they exert pressure on the surface on which they are incident.